402 ANNUAL REPORT OF THE Off. Doc. 



part, supplementing it from time to time as I go along, with what 

 occur to me as being of interest to the subject before us, 



"When Nature is left to itself, the soil does not lose, but gains in 

 fertility." The annual growth of vegetation falls upon the land, 

 covering the growths of previous j^ears, which are gradually incor- 

 porated with the soil through the processes of decay and the action 

 of worms, ants, and other burrowing insects and animals, each year's 

 growth adding to the total stock of available plant food a little fresh 

 material, which has been wrested from the rocky particles in the 

 soil by solution in water, and by the work of micro-organisms and 

 other agencies to which we apply the term "weathering:" so that 

 each succeeding springtime finds the soil of the wild forest or prairie 

 a little more fertile than the one before. 



It would seem that if the land were pastured, or if all its produce 

 were fed to the livestock and the manure returned, a similar increase 

 in fertility should take place, and many farmers practice the keeping 

 of livestock with this end in view; but a little consideration will 

 show tliat there may be losses of fertility from the stock farm 

 closely approaching those of the farm from which all produce is sold. 



The growing animal is constantly building a skeleton, which 

 serves as a framework to support its vital organs. This skeleton is 

 composed chiefly of two elementary substances, both obtained from 

 the soil, namely: phosphorus and calcium, united with each other 

 in the combination known as phosphate of lime. 



Where animals are grown upon pasture, therefore, and then sent 

 to market, there is a steady drain from the soil of these two ele- 

 ments. The losses of nitrogen and potassium will be relatively 

 smaller, because there is constantly some restoration of nitrogen 

 from the small amount of combined nitrogen annually brought down 

 in rain, and from the much larger mount which may be secured by 

 the nitrogen — fixing organisms in the soil, while the amount of 

 potassium carried away is extremely small, and is usually com- 

 pensated by the weathering of the large supply of this element found 

 in most soils. 



If animals are pastured for milk production instead of for growth, 

 the draft upon the bone-building elements is still greater, as is 

 easily understood when we watch the rapid growth of a suckling calf, 

 and a good dairy cow will produce enough milk in a year to raise 

 two or three calves. 



It is during the winter months that the great losses in fertility 

 occur in livestock husbandry; for then not only are the phosphorus 

 and calcium of the feed drawn upon for skeleton-building or milk 

 production, but unless the manure is very carefully saved there will 

 be large losses of nitrogen and potassium also. 



Thinking farmers have long realized that these losses must be con- 

 siderable, and several experiment stations have studied the question. 

 At the Ohio station we have endeavored to learn how much of the 

 fertilizing elements contained in the feed it is possible to recover in 

 the manure, and what the losses in this manure are under different 

 systems of handling. When cattle were fed on cemented floors, we 

 were able to recover in the manure three-fourths of the nitrogen and 

 eighty to ninety per cent, of the phosphorus and potassium con- 

 tained in the feed and bedding, but on earth floor, though fed under 



